Typically an aircraft chaff dispenser includes:                an elongated hollow housing intended to be fixed to the fuselage or to a wing so as to be oriented in the longitudinal direction of the aircraft, the housing having a closed front end and an open rear end;        a driving mechanism received inside the housing and operable to push backwards (relative to the direction of forward movement of the aircraft) packets of chaff and eject them one at a time from the rear opening; and        an electronic circuit controlling the driving mechanism, and, where applicable, part of the aircraft defence sensor equipment and electronic circuitry.        
The packets of chaff ejected from the rear of the dispenser “explode” as a result of the air striking them and thus disperse the chaff into the air wake of the aircraft.
The main problem affecting the known aircraft chaff dispenser consists in that a negative pressure gradient is created between the front part of the housing (in which the driving mechanism is received) and the rear part of the housing (in which the packets of chaff are received and from which they are ejected), which negative pressure gradient causes the chaff ejected from the chaff dispenser to be sucked back into or recirculated inside it, with a consequent risk of faults both of a mechanical nature, such as seizing of the driving mechanism, and of an electronic nature, in particular problems of electromagnetic interference with the electronic control circuits of the dispenser and with the remaining aircraft defence circuitry and sensor equipment mounted on the housing of the dispenser. In order to overcome this problem it is known to provide air intakes on the front of the side walls of the dispenser housing, so as to increase the pressure at the front of the housing. The presence of lateral air intakes involves, however, the risk that the gases emitted by the missiles launched by the aircraft enter inside the dispenser and hit the packets of chaff contained inside it, damaging them irremediably and therefore negatively affecting the defence capacity of the aircraft.